Location based services (LBS for short) are also called mobile location services or positioning services, which mean that a mobile network obtains geographical location information (latitude and longitude coordinates) of a mobile terminal via a specific positioning technology, provides the information to a mobile subscriber per se, a communication system, or a third party, and then provides location-related call or non-call services to the mobile subscriber with certain support of electronic map information.
Positioning manners of a mobile communication network comprise cell-based positioning, traditional GPS-based (global positioning system, GPS for short) positioning, AFLT-based (advanced forward link trilateration, AFLT for short) positioning, and AGPS (assisted GPS) positioning, etc., wherein the AGPS positioning, which combines GPS positioning and a mobile communication system, has been widely applied due to its fast positioning speed and high positioning accuracy.
FIG. 1 shows an entity architecture diagram of an AGPS-based positioning system of a mobile communication network system subscriber. The positioning system mainly comprises a mobile station, a mobile positioning center, a positioning entity, a GPS satellite signal receiver, and a GPS satellite, wherein
the mobile station is a user end equipment of the positioning services, and its main function is to provide measurement information related to mobile terminal positioning, implement signaling interactions with the positioning entity via the mobile communication network, and accomplish a part of applications of the positioning services. The mobile station may also download auxiliary data from the positioning entity and implement location calculation, which is determined by a mobile station chip.
The mobile positioning center is a core entity for implementing the positioning services, and its main function is to control a positioning process, interact with each positioning entity, and store and provide subscriber location information, etc.
The main function of the positioning entity is to process information sent from the mobile station to a network side, and based on the base station geographic location information and GPS satellite data which are managed by the positioning entity, to calculate the location of the mobile terminal or provide the auxiliary data required for measurement for the mobile station, the auxiliary data includes the auxiliary data for searching the GPS satellite and base station geographic location information data for calculating location.
The main function of the GPS satellite signal receiver is to receive GPS satellite signal data and send the data to the positioning entity.
The function of the GPS satellite is to send real-time satellite signal data.
The current positioning methods may refer to the industrial standards “technical specifications on user plane-related devices for 800 MHz CDMA digital cellular mobile communication network V2 positioning services” and “specifications on mobile stations for China Unicom CDMA1X digital cellular mobile communication network” released by China Unicom, the industrial standard “specifications on China Telecom CDMA network positioning services devices” released by China Telecom, and the international standard “ANSI TIA/EIA-IS-801 position determination service standard for dual mode separate spectrum systems”, wherein the CDMA is code division multiple access.
However, the continuous positioning flow in an existing network fails to consider abnormal situations of power off or restart of the mobile station during the positioning process.
FIG. 2 is a flowchart illustrating a track-type continuous positioning process initiated from a network side in an existing network, and the process comprises the following steps:
step S21, a positioning client initiates a positioning request for a mobile station to a mobile positioning center, and requests to perform a track-type continuous positioning for the mobile station;
step S22, the mobile positioning center sends a short message induced positioning request to the mobile station;
step S23, the mobile station initiates a starting positioning process request;
step S24, the mobile positioning center selects a corresponding positioning entity and sends a geographic location information request to the positioning entity;
step S25, the positioning entity returns a geographic location information response message to the mobile positioning center, and indicates that the positioning may be started;
step S26, the mobile positioning center returns a starting positioning request response to the mobile station, and indicates an IP address and a port number of the positioning entity;
step S27, the mobile positioning center assigns a task identification for this positioning and returns a location request response to the positioning client;
step S28, the mobile station performs location data interactions with the positioning entity, and downloads auxiliary positioning data, etc.;
step S29, the positioning entity, after completing final location calculation, sends a geographic location result to the mobile positioning center;
step S210, the mobile station sends a location report to the mobile positioning center;
step S211, the mobile positioning center returns a location report response to the mobile station;
step S212, the mobile positioning center sends the location result of the mobile station to the positioning client;
step S213, after a while, the mobile station obtains current wireless cell parameters, and sends a location report containing cell information to the mobile positioning center;
step S214, the mobile positioning center returns a location report response to the mobile station; and
step S215, the mobile positioning center sends the location result of the mobile station to the positioning client.
In the continuous flow of the existing network, for the mobile positioning center and the positioning entity, once the track positioning starts, the continuous positioning flow will not be terminated and the resource will not be released until the time for terminating tracking arrives. However, in practical application, circumstances of power off or restart of the mobile station occur frequently during the continuous positioning process, and in such cases, the mobile station will not continue interacting with the positioning entity or send the location result to the mobile positioning center, and in fact at this point, the continuous positioning flow has terminated. It will cause the following consequences:
firstly, the resources of the mobile positioning center and the positioning entity cannot be released in time, which reduces performance of the positioning system and efficient utilization of resources; and
secondly, in some special application circumstances (for example, logistic tracking for major businesses, tracking of a security department to some mobile stations), after the mobile station state resumes normal, the positioning client cannot timely and effectively obtain the latest location of the mobile station.